Contact fuzing system



A 29, mm E. F. FOHRMANN ET L 3,

CONTACT FUZING SYSTEM Filed Nov. 17. 1966 Sheet of 2 ENABLING OUTPUTSWTCH cmcuw 0 TRIGGEFHNG DEVICE TRIGGERING 26 28 DEVICE 7 LOW PASS PEAKH8 FILTERS DETECTOR AND DC AND v FULLWAVE COUPLER BLOCKING SSESQRECTIFIER OSC|LLATOR AND MIXER T 24 lZ BUFFER 22 AMPUFIER TRIGGERKNG ANDLIMITER DEVICE ADJUST ERNEST F. FOHRMANN DAVID A SCOLES BENJAMIN T.COCHRAN TRlGGERING JOHN W DEVICE INVENTORS BYQW W? fw w ATTORNEYSCONTACT FUZ ING SYSTEM Filed NOV. 17, 1966 E. F. FOHRMANN ET AL.

sheetiofz ERNEST F. FOHRMANN DAVID A. SCOLES BENJAMIN T. COCHRAN JOHN O.DICK INVENTORS ATTORNEYS United States US. Cl. 102-70.2 2 ClaimsABSTRACT OF THE" DISCLOSURE A contact fuzing system for providing aplurality of triggering elements Without one triggering elementinterfering with another. A plurality of triggering elements positionedover an area of expected impact with a target are coupled by means of anisolating circuit to the processing circuit which generates the firingpulse.

The invention herein described may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

The present invention relates to contact fuzing systems and moreparticularly to contact fuzing systems having multiple triggeringelements.

For greater reliability of the ignition of a contact type fuze, it hasbeen found necessary to install multiple triggering devices positionedover an area of that portion of the missile expected to collide with thetarget. It is also desirous that the contact fuze will initiate themissile warhead on the first shock pulse reaching anyone of the varioustriggering devices. The present invention provides a contact fuze systemwhich will accomplish the above requirements by initiating the warheadwhether the shock pulse is negative or positive and provides isolationof the signals generated by the triggering devices to prevent distortionof the initial triggering signal.

Accordingly, an object of the present invention is to provide animproved contact fuze system which utilizes multiple triggering deviceswithout interference of one triggering output signal with any of theother triggering output signals.

Other objects and many of the attendant advantages of this inventionwill become readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is illustrative of a missile with a plurality of fuze triggeringdevices positioned on its outer surface.

FIG. 2 is a block diagram of a preferred embodiment of the invention.

FIG. 3 is a schematic diagram of the embodiment of FIG. 2.

Referring now to the drawings there is shown in FIG. 1 a missile havinga plurality of triggering devices 12 strategically located on itsforward portion. Devices 12 are positioned on each of the wing hubs 14and near the nose of the missile on a structural member 16 near the skinsurface of the missile 10. These positions are selected so that if anyportion of a wing or a portion near the nose is impacted, the shock wavewill be transmitted to the triggering devices 12.

Referring to FIG. 2, any shock wave detected by any of triggeringdevices 12 produces output signals which are fed to fullwave rectifierand mixer 18. The output signal from fullwave rectifier and mixer 18 ispicked off by the movable tap 20 of a potentiometer 22.

The signal appearing at movable tap 20 is fed to butter amplifier andlimiter 24 which isolates the remainder of the circuit from triggeringdevices 12. This is necessary so that the inductance and capacitance ofthe filter circuit of low pass filters and DC coupler 26 will not reactwith electromechanical properties of the triggering devices 12 and causeresonant humps in the frequency response. The output from low passfilters and DC coupler is fed to peak detector and blocking oscillator28 which provides an output signal to output circuit 30 when theblocking oscillator is triggered by a detected signal of a predeterminedamplitude. In order to minimize the probability of an early firing,supply voltage to output circuit 30 is supplied by enabling switch 32just prior to anticipated intercept of the target.

Referring to the schematic diagram of FIG. 3, any signals generated bytriggering devices 12 (FIG. 1) are fed through input resistors 13 to theprimary windings of full wave rectifier transformers 15. Thecentertapped secondaries of transformers are connected to diodes 17 forfull wave rectification. The outputs from rectifiers 17 are connected tothe fixed terminal potentiometer 19. The full wave rectified signals donot add because the maximum signal at any instant back biases the otherrectifier diodes, therefore, the instantaneous mixer output amplitude isproportional to the triggering device output which is instantaneouslymaximum.

The gain of the output signal from full wave rectifier 18 may beattenuated by means of adjusting movable tap of potentiometer 19. Thesignal picked off by movable tap 20 is coupled to the base of transistor25 which acts as an isolator to isolate filter 26 from the triggeringdevices 12 and to limit the output signal to approximately 1.4 times theamplitude of a signal which would produce a fuze firing signal. Resistor51 and Zener diode 53 act as a voltage regulator to keep the voltageacross resistors 55 and 57 constant. The voltage applied to thecollector of transistor 25, when it is non-conducting, is the result ofthe Zener regulated voltage and the divider ratio of resistors 55 and57. The open circuit (nonconducting) voltage of transistor 25 and itssource impedance determine the voltage level at which amplifier 24 willlimit.

Low pass filter 26 should have filter roll-off characteristics such thatthe amplitude of its output to peak detector 28 at 12,500 c.p.s. isapproximately 0.7 of that which would occur at 8,000 c.p.s. with thesame gain adjustment and input signal amplitude. The expression, limiteroutput X filter gain input to peak detector, defines the filter limiteraction.

The output of low pass filter 26 is coupled through capacitor 27 to theinput of peak detector and blocking oscillator 28. The peak detectorconsists of a reversebiased transistor 29 which provides a blockingoscillator pulse when the input at its base exceeds the reverse bias.Resistor 31 should be of a sufiicient value to hold the blockingoscillator in a quiescence state. When a positive DC signal exceedingthe preset bias value is applied to the base of transistor 29, theblocking oscillator will free run at a predetermined frequency.

Output circuit releases electrical energy stored in capacitor 33 tooutput terminal 35. The above is accomplished as follows: as theblocking oscillator pulses a signal is coupled into winding 37 oftransformer 39 to drive the gate of silicon controlled rectifier 40positive with respect to the cathode, thus, allowing capacitor 33 todischarge.

Under missile flight conditions, +265 v. DC is applied to terminal 41energizing all of the circuit up to but not including, the outputcircuit 330. Capacitor 33 will not be charged until it is connected toan energizing voltage at terminal 42 when a signal is applied (from themissile) to terminal 43 to energize relay coil 44 which closes relay 45.

What is claimed is: 1. In a contact fuze system for a missile carrying awarhead to be exploded on contact with a target, the combinationcomprising:

(a) a plurality piezoelectric means positioned at vari- 5 ous positionsof expected impact between the missile and target and being responsiveto acceleration forces as a result of an impact between the target andmissile to generate voltages proportional to acceleration,

(b) a plurality of transformers, each having a primary Winding and acentertapped secondary winding,

(0) one end of each of said primary windings and the centertaps of saidsecondary windings being connected to a common ground,

(d) the other end of each of said transformer windings being connectedrespectively to one of said piezoelectric means,

(e) dual diode fullwave rectifier means connected across each of saidsecondary windings,

(f) a potentiometer having a movable tap and being connected between theoutputs of said fullwave rectifier and the common ground, whereby themaximum voltage generated by any one of said piezoelectric means willappear at the movable tap of said potentiometer,

(g) signal processing circuit means coupled to said movable tap forgenerating a fuze firing pulse in response to the voltage output of saidcoupling means.

2. The contact fuze system of claim 1 wherein said signal processingcircuit comprises:

(a) a buffer amplifier and limiter coupled to the output of saidisolation coupling means,

(b) low pass filter circuit means having a filter gain less than 0.70for all frequencies greater than 12.5 kc. coupled to the output of saidbutler amplifier,

(c) peak detector circuit means including a blocking oscillator coupledto said low pass filter circuit means for generating an output signalwhen the output of said buffer amplifier reaches a predetermined value.

References Cited UNITED STATES PATENTS 3,080,521 3/1963 Euker et al.102-702 X 3,239,678 3/1966 Kolm et al 102-70.2 X 3,275,884 9/1966 Segallet al. 102-702 X VERLIN R. PENDERGRASS, Primary Examiner.

